Abstract The structure of the lichen depsidone grayanic acid (1)(6-heptyl-8-hydroxy-3- methoxy-1-methyl-11-oxo-11H-dibenzo [b, e][1, 4] dioxepin-7-carboxylic acid) proposed by Shibata and Chiang was confirmed by the synthesis firstly of methyl O-methylgrayanate (19), and then of grayanic acid itself. The key step in both syntheses was an Ullmann reaction.
